Failed to establish a new connection: [Errno 11002]

[vipulswarup]

I have successfully run "python download.py" and a number of files have been downloaded. But after a while I get the below error:

Error occoured: HTTPSConnectionPool(host='czds.icann.org', port=443): Max retries exceeded with url: /en/download-zone-data/3659?token=XXXXXXXXXXXXXXX (Caused by NewConnectionError('<urllib3.connection.VerifiedHTTPSConnection object at 0x030300F0>: Failed to establish a new connection: [Errno 11002] getaddrinfo failed',))

(I have replaced the actual token in the error message with XXXXXXXX)

When I rerun the script, it seems to run for some time and then again the same error. This is on Windows 10, using Python 2.7

Any ideas?